The association between OD and cognitive decline is becoming apparent in the emerging literature. However, the literature demonstrating a similar effect between GD and cognition is not well established.

Researchers conducted this study to determine whether OD and GD are independently associated with cognitive impairment.

The National Health and Nutrition Examination Survey was queried for 1376 older adults, corresponding to a weighted population sample of 50 816 529, to assess the olfactory and gustatory status and cognition univariate and multivariate regression analyses. OD and GD were determined using objective measurements with validated protocols. Participants were stratified as normal or abnormal cognition status using accepted cutoff values as indicated for the CERAD neuropsychological test, AFT, and DSST.

OD was associated with mild cognitive impairment and dementia with CERAD testing, abnormal AFT, and abnormal DSST. GD based on 1M NaCl whole mouth taste testing was associated with dementia on CERAD testing. Researchers included smell and taste parameters together in the regression mod. Both OD and GD remained significant independent predictors of dementia status based on CERAD testing.

The study concluded that OD and severe GD represent independent predictors of cognitive impairment in a nationally representative sample of older adults.